The invention relates to tubular members and more specifically to elongated flexible tubular ducts of a flexible material and to the longitudinal joint herein and to the method of making such jointed ducts.
Tubular members, and more specifically flexible tubular ducts, serve a variety of needs. For example, they may be required to convey gases, without substantial leakage, at a pressure other than ambient. There may additionally be thermal considerations requiring insulation, as in air conditioning ducts. Still further, the ducts may be required to possess some degree of flexibility to facilitate installation.
It is an object of the invention to provide a elongated tubular member which is formed of a flexible material and which includes a durable and tight joint. Still another object of the invention is the provision of a substantially flat joint or seal on the inside surface of the tubular casing of an elongated tubular duct having an insulating liner and skeletal member therewithin.
It is a further object of the invention to provide a method of making a longitudinal joint or seal in an elongated tubular member. A still further object is the provision of a method of forming a longitudinal joint in a substantially continuous tubular member of flexible material, which method is readily suited to automation. Further, it is an object to provide a method of making a tubular duct having an inner, annular support member and insulating portion and an outer longitudinally jointed, casing embracing the insulating portion.